B3.2.3Irrigation techniques Sprinkler irrigation

1
B3.2.3 Irrigation techniquesSprinkler irrigation

• Uniform application by artificial rain
• Good application efficiencies (0.7 0.8)
• dependent on wind, temperature, humidity
• Fairly terrain independent (but design must take
  terrain into account)
• Can have a low labour content
• But
• High(ish) investment cost
• High maintenance cost due to pumping
• Can be complex to run

2
B3.2.3 Irrigation techniquesSprinkler
irrigation Criteria(from Cornish)

• Must permit cost recovery within one to two years
  (and double investment in a short time)
• Must be suitable for use on small and irregular
  shaped plots
• Must require only simple maintenance and tools
• Have a low risk of component failure
• Be simple to operate
• Be durable and reliable able to withstand rough
  and frequent handling without serious damage

3
B3.2.3 Irrigation techniquesSprinkler
irrigation System layout
4
B3.2.3 Irrigation techniquesSprinkler irrigation
5
B3.2.3 Irrigation techniquesSprinkler
irrigation Drag hose system
6
B3.2.3 Irrigation techniquesSprinkler
irrigation Sprinkler
7
B3.2.3 Irrigation techniquesSprinkler
irrigation Spray pattern
8
B3.2.3 Irrigation techniquesSprinkler
irrigation Spray pattern
9
B3.2.3 Irrigation techniquesSprinkler
irrigation Spray pattern Variation in pressure
10
B3.2.3 Irrigation techniquesSprinkler
irrigation Variation in pressure
11
B3.2.3 Irrigation techniquesSprinkler
irrigation Solid set system
12
B3.2.3 Irrigation techniquesSprinkler
irrigation Hand move laterals
13
B3.2.3 Irrigation techniquesSprinkler
irrigation Hop along system
14
B3.2.3 Irrigation techniquesSprinkler
irrigation Drag hose system
15
B3.2.3 Irrigation techniquesSprinkler
irrigation Drag hose system
16
B3.2.3 Irrigation techniquesSprinkler
irrigation Centre pivot system
17
B3.2.3 Irrigation techniquesSprinkler
irrigation Centre pivot system
18
B3.2.3 Irrigation techniquesSprinkler
irrigation Centre pivot system
19
B3.2.3 Irrigation techniquesSprinkler
irrigation Centre pivot system
20
B3.2.3 Irrigation techniquesSprinkler
irrigation Linear move system
21
B3.2.3 Irrigation techniquesSprinkler
irrigation Linear move system
22
B3.2.3 Irrigation techniquesSprinkler
irrigation Linear move system
23
B3.2.3 Irrigation techniquesSprinkler
irrigation Mobile raingun
24
B3.2.3 Irrigation techniquesSprinkler
irrigation Mobile raingun
25
B3.2.3 Irrigation techniquesSprinkler
irrigation Appropriateness
Type Divisibility Maintenance Risk Operator skill Durability
Hand move 3 2 2 2 3
Drag Hose 3 4 2 3 3
Low-tech 3 4 3 3 3
Perforated pipe 3 2 1 3 2
Side roll 0 2 2 2 2
Side move 0 1 1 1 1
Static gun 2 2 2 1 3
Boom 0 2 1 1 2
Traveling gun 2 1 1 1 2
Centre Pivot 0 1 1 1 2
Liner move 0 1 1 1 2
Solid set 3 3 2 3 3
Piped distribution 3 3 3 3 4
26
B3.2.3 Irrigation techniquesSprinkler
irrigation Appropriateness
Type Score Crops
Piped distribution 16 All
Low tech 16 All
Drag hose 15 All
Solid set 14 Orchards
Hand move laterals 12 All
Perforated pipe 11 Soft fruit and veg
Static gun 10 Cereals, Row crops
Side roll 7 Short cereals, row crops
Traveling gun 7 Cereals, Row crops
Boom 6 Cereals, Row crops
Centre pivot 5 Cereals, Row crops
Linear move 5 Cereals, Row crops
Side move 4 Cereals, Row crops
27
B3.2.4 Irrigation techniques Micro irrigation

• Excellent efficiency (gt0.9)
• little and often - plants have ideal water all
  the time
• As little as 30 of the root zone is wetted
• Not sensitive to slope
• Good for mineralised water
• Good for injected fertiliser
• But
• Very expensive
• Needs well filtered water
• Can be complex to operate ands maintain

28
B3.2.4 Irrigation techniquesMicro irrigation
Improvements
Crop Yield Increase () Water saving ()
Bananas 52 45
Grapes 23 48
Sweet lime 50 61
Pomegranate 98 45
Papaya 75 68
Tomato 50 39
Watermelon 88 36
Okra 16 40
Cabbage 2 60
Chillies 44 62
Sweet Potato 39 60
Beetroot 7 79
Radish 2 77
Sugar cane 33 56
Cotton 26 53
29
B3.2.4 Irrigation techniquesMicro irrigation
Layout
30
B3.2.4 Irrigation techniquesMicro irrigation
Drip irrigation
31
B3.2.4 Irrigation techniquesMicro irrigation
Root zone
32
B3.2.4 Irrigation techniquesMicro irrigation
Infiltration
Sandy soil
Clay soil
33
B3.2.4 Irrigation techniquesMicro irrigation
Emitters
34
B3.2.4 Irrigation techniquesMicro irrigation
Thick walled drip hose
35
B3.2.4 Irrigation techniquesMicro irrigation
Thin walled drip hose
36
B3.2.4 Irrigation techniquesMicro irrigation
Bubblers
37
B3.2.4 Irrigation techniquesMicro irrigation
Microsprinklers
38
B3.2.4 Irrigation techniquesMicro irrigation
Microsprinklers
39
B3.2.4 Irrigation techniquesMicro irrigation
Appropriateness
Type Divisibility Maintenance Risk Operator skill Durability
Drip emitters 3 3 1 1 1
Drip hose (thick) 3 3 1 1 1
Drip hose (thin) 3 3 1 1 1
Micro sprayers 3 3 2 1 3
Pressurised bubbler 3 3 3 3 4
Gravity fed bubbler 3 3 3 1 2
40
B3.2.4 Irrigation techniquesMicro irrigation
Appropriateness
Type Score Crops Cost (USD 1990)
Piped distribution 16 All 800
Low tech Sprinkler 16 All
Pressurised bubbler 16 Orchard 3,000
Drag hose Sprinkler 15 All 675
Solid set Sprinkler 14 Orchards 3,500
Hand move laterals Sprinkler 12 All 675
Micro sprayers 12 Orchard, Soft fruit and 3,500
Gravity fed bubbler 12 Orchard 3,500
Perforated pipe Sprinkler 11 Soft fruit and vegetables 800
Static gun Sprinkler 10 Cereals, Row crops 950
Drip emitters 9 Wide row fruit and vegetables 3,500
Drip hose (thick) 9 Wide row fruit and vegetables 5,000
Drip hose (thin) 9 Wide row fruit and vegetables 3,000
Side roll Sprinkler 7 Short cereals, row crops 1,500
Traveling gun Sprinkler 7 Cereals, Row crops 1,500
Note Skilled workers wages in Sri Lanka 4/day,
Uganda, 2.5/day
41
B3.2.4 Irrigation techniquesMicro irrigation
AppropriatenessMethods based on imported
components

• Manufactured drip emitters and microsprayer
  assemblies are carefully supervised and
  maintained.
• Ancillary equipment such as screen and media
  filters, metering valves, pressure regulators and
  fertilizer injectors are used in various
  combinations.
• Note These options will be justified only for
  cash crops in a stable market economy.

From Small-scale irrigation for arid zones
Principles and options http//www.fao.org/docre
p/w3094e/w3094e00.htm
42
B3.2.4 Irrigation techniquesMicro irrigation
AppropriatenessMethods based on imported
materials but local fabrication

• Moulded plastic pipes or extruded plastic tubing
  are perforated manually and laid over the ground
  to simulate drip irrigation.
• Vertical sections of plastic pipes (or even
  discarded plastic containers such as bottles) are
  embedded in the ground.
• Thin-walled plastic vessels are filled with sand
  or gravel to provide mechanical resistance to
  crushing.

43
B3.2.4 Irrigation techniquesMicro irrigation
AppropriatenessMethods based on imported
materials but local fabrication

• Slit plastic sleeves cover the perforated
  sections of the tubes to prevent root penetration
  into the outlet holes.
• Sand filters prevent suspended particles or algae
  from clogging the outlets.
• Auxiliary containers are used to dissolve and
  inject fertilizer into the irrigation water.
• Vertical standpipes are used to deliver water
  from an underground pipe to small basins.

44
B3.2.4 Irrigation techniquesMicro irrigation
AppropriatenessMethods based entirely on local
materials and workmanship

• Low-fired porous ceramic pots are placed on the
  surface or embedded in the soil within the root
  zone. When filled with water and dissolved
  fertilizers, the permeable clay receptacles ooze
  water and nutrients into the soil.
• Sectioned ceramic pipes constitute line sources
  that feed elongated beds.

45
B3.2.4 Irrigation techniquesMicro irrigation
Appropriateness Clay pot method
46
B3.2.4 Irrigation techniquesModern irrigation
technologies Appropriateness(from Cornish)

• The technology must offer the farmer sufficient
  financial return or a reduction in labour demand,
  to justify the investment
• Farmers need to grow high value crops for an
  assured market in order to cover costs
• Increasing national or regional water shortage is
  an important factor motivating governments to
  promote the use of modern irrigation technologies

47
B3.2.4 Irrigation techniquesModern irrigation
technologies Appropriateness

• Governments must enact policies promoting the
  technologies for the smallholder, making it
  attractive to manufacturers and dealers to
  develop and promote them
• Suitable systems must be relatively cheap and
  straightforward to operate and maintain
• Farmers require effective technical support in
  the initial years failure ruin